From owner-freebsd-hackers Sat May 16 05:33:25 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id FAA09170 for freebsd-hackers-outgoing; Sat, 16 May 1998 05:33:25 -0700 (PDT) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from labinfo.iet.unipi.it (labinfo.iet.unipi.it [131.114.9.5]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id FAA09163 for ; Sat, 16 May 1998 05:33:19 -0700 (PDT) (envelope-from luigi@labinfo.iet.unipi.it) Received: from localhost (luigi@localhost) by labinfo.iet.unipi.it (8.6.5/8.6.5) id MAA04082; Sat, 16 May 1998 12:49:03 +0200 From: Luigi Rizzo Message-Id: <199805161049.MAA04082@labinfo.iet.unipi.it> Subject: bad behaviour in slow start To: hackers@FreeBSD.ORG Date: Sat, 16 May 1998 12:49:03 +0200 (MET DST) X-Mailer: ELM [version 2.4 PL23] Content-Type: text Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG I noticed this a couple of years ago, but the problem appears to be still there in -stable. In tcp_input.c there is an "optimization" that disable slow_start on local networks. This was introduced in version 1.11 of the file. The relevant lines are: /* * Don't force slow-start on local network. */ if (!in_localaddr(inp->inp_faddr)) tp->snd_cwnd = mss; I think this is in violation of good TCP practices, and should be at the very least made optional, controlled by a sysctl variable which defaults to off: static int no_slowstart_on_local_net = 0; SYSCTL_INT(_net_inet_tcp, OID_AUTO, no_slowstart_on_local_net, CTLFLAG_RW, &no_slowstart_on_local_net, 0, ""); ... if (!no_slowstart_on_local_net || !in_localaddr(inp->inp_faddr)) tp->snd_cwnd = mss; comments ? luigi -----------------------------+-------------------------------------- Luigi Rizzo | Dip. di Ingegneria dell'Informazione email: luigi@iet.unipi.it | Universita' di Pisa tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/ _____________________________|______________________________________ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message